Commutator-brush and brush-holder.



Yu 7 504 Patented Apr. 23, l90l.

v 1 R. LUND-ELL.v

COMMUTATOB BRUSH AND BRUSH HOLDER.

(Application filed om 10, 1900. (N 0 M o d a l UNITED STATES PATENTOFFICE.

ROBERT LUNDELL, OF NEW YORK, N. Y.

COMMUTATOR-BRUSH AND BRUSH-HOLDER.

SPECIFICATION forming part of Letters Patent No. 672,604, dated April23. 1901.

' Application filed October 10, 1900. Serial No. 32,572. QNo modelh Toall whom, it may concern:

Be it known that I, ROBERT LUNDELL, a citizen of the UnitedStates,residingat New York, borough of Manhattan, county and State ofNew York, have made a new and useful Invention in Oommutator-Brnshes andBrush- :Iolders for Dynamo-Electric Machines or Electric Motors, ofwhich the following is a .pecification.

The present invention relates to improvenents in commutator-brushholders and )rushes, and has particular reference to that class ofbrushes whicli'are known as carbon brushes. It has for its objects,first, to reuce the heating by decreasing the total or ggregate contactresistance between the arushes and commutator; second, to preventsparking (a) by increasing the contact resisttnce at the points where ahigh brush resist- M306 is needed to insure perfect commutaion, and (b)by decreasing the possibility of )reaking contact, owing to any slightunevenness on the surface of the commutator, and, third, to providemeans for taking up the differentamounts of wire of the brushes due totheir different qualities.

It is well known in the art that a low-resistance brush is desirable inorder to keep the 0 R losses within proper limits; but that ahigh-resistance brush is needed to prevent sparking in cases where thebrushes cannot be given the proper amount of lead on the commutatorforexample, railway-motors,

which must run in both directions without change of brush position.

Carbon brushes are now made with high-resistance edges andlow-resistance centers, which seem to work quite well if the currentdensity is low and other conditions favorable. I have, however, foundthat when these brushes are used under more severe conditions the centerportion of the brush is eaten out until only the high-resistance edgesmake contact with the commutator. The present invention overcomes thisdiificulty and provides means for preventing rupture of contact, owingto a slight unevenness on the surface of the commutator, which ruptureof contact would quickly aggravate the fault.

Referring now to the drawings, Figure 1 is a side elevational view of mynovel brushholder and brush; and Fig. 2 is a sectional view of the same,taken at line 00 03 of Fig. 1.

Referring now to the drawings in detail, B, B, and B represent threecarbon brushes which are pressed against the commutator, as shown,independent of one another by separate springs 8,8, and S The carbonsare arranged to slide in hollow sleeves or guides contained in a holderH, which in turn is firmly secured to a rocker-arm or other support inthe usual manner. The center carbon B is supposed to be made of speciallow-resistance material and may have a layer of fine copper gauzeembedded in the center of its body, according to usual practice. To theupper part of the carbon, which is copper-plated, is soldered a copperpiece A, to which in turn is soldered a flexible copper cable 0, theobject being to provide a path of very low resistance from the commutator-bars to the fixed part of the holder. Aspiralspring S andadjusting thumb-screw Tare provided between the extension H of thebrush-holder and the brush-holder I-I itself in order to put therequisite pressure upon the carbon. The two outside carbons are supposedto be made ofhigh-resistance material. They are pressed against thecommutator by flat springs S and S as clearly indicated in the drawings.The arrangement and construction of said springs are similar to the onedescribed by me in a prior United States patent, No. 505,665, ofSeptember 26, 1893, and a minute description of the details is for thisreason not considered necessary. It will of course be understood that ifthe dynamoelectric machine is to run in only one direction theconstruction of the brush -holders would be somewhat simpler, by reasonof the fact that one of the highresistance brushes could be omitted.

I do not limit my invention to the specific details of structure andarrangement as to its application shown in theaccompanying drawings orhereinbefore described. I believe it is broadly new with me to combinetwo or more commutator-brushes of different conductive capacity and tolocate them side by side upon the commutator of a dynamo-electriomachine or electric motor, each brush being secured in its position byan independent support and provided with independent means for feedingit forward as its contacting end is worn away by the commutator, and myclaims hereinafter made are generic as to this feature.

Having thus described my invention, what I claim, and desire to secureby Letters Patent of the United States, is

1. Two or more commutator-brushes of different resistance secured inindependent supports of a brush-holder, and in such relation to eachother that a high-resistance brush is located at the leaving edge of thelow-resistance brush; in combination with means for causing said brushesto be fed forward independently of each other, substantially asdescribed.

2. A brush-holder having three sets of independently-supported brushes,the center brush or brushes being of lower resistance than the two outersets of brushes for the purpose of preventing sparking on thecommutator; in combination with means for causing said brushes to be fedforward independently of each other.

A current-collecting device for a commutator consisting of severalindependently-supported brushes of carbon or other similar unyieldingmaterial located after one another on the periphery of the commutator,substantially as described.

4. A current-collecting device fora com mutator consisting of severalbrushes located after one another on the periphery of the com- 111utator, said brushes being held by independent supports or pockets,which in turn are electrically united so as to constitute parts ofeithera positive or a negative brush-holder.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

ROBERT LUNDELL.

Witnesses:

C. J. KINTNER, M. F. KEATING.

Correction in Letters Patent No. 672,604, f

It is herebg certified that in Letters Patent No. 672,604, granted April23, 1901,

upon the application of Robert Lundell, of New York, N. Y., for animprovement in Oommutator-Brushes and Brush-Holders, an error appears inthe printed specification requiring correction, as follows: In line 25,page 1, the Word wire should read wear; and that the said Letters Patentshould be read With this correction therein that the same may conform tothe record of the case in the Patent Office.

Signed, countersigned, and sealed this 7th day of May, A. 1).,1901.

[SEAL] F. L. CAMPBELL,

Assistant Secretary of the Interior.

Oountersigned F. I. ALLEN,

Commissioner of Patents.

Correction in Letters PatentNo. 672,604.

It is herehg certified that in Letters Patent No. 672,604, granted April23, 1901, upon the application of Robert Lundell, of New York, N. Y.,for an improvement in Commutator-Brushes and Brush-Holders, an errorappears in the printed specification requiring correction, as follows:In line 25, page 1, the word wire should read wear,- and that the saidLetters Patent should be read with this correction therein that the samemay conform to the record of the case in the Patent Office.

Signed, countersigned, and sealed this 7th day of May, A. D., 1901.

[SEAL] F. L. CAMPBELL,

Assistant Secretary of the Interior.

Oonntersigned F. I. ALLEN,

Commissioner of Patents.

